Net Income per Share (Schedule Of Net Income Per Share To Shareholders) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Earnings Per Share [Abstract]
Net income to shareholders	$ 57,253	$ 8,272
Basic common shares outstanding	9,642	9,717
Dilutive potential common shares	29	40
Diluted shares outstanding	9,671	9,757
Basic net income per share	$ 5.94	$ 0.85
Diluted net income per share	$ 5.92	$ 0.85